You would need to speak to a hacker or some such person to get the answer to that question. What I can tell you as a lawyer is that evidence obtained in this way is not admissible. It is a breach of privacy. Because such information will have been obtained unlawfully the courts will not allow the perpetrator to use it in the family courts. Indeed, if your wife disclosed to your solicitor that she had such information they would be obliged to notify you and to destroy all copies in their possession.
In UL v BK (Freezing Orders: Safeguards: Standard Examples)10 Mostyn J provided a pithy guide to dealing with this type of issue (at ยง56):
>>i) Whatever the historic practice (and however alluring the arguments for pragmatism and practicality) it is simply and categorically unlawful for a wife (for it usually is she) to breach her husband's privacy by furtively copying his documents whether they exist in hard copy or electronically. There may be factual issues about whether the documents are actually in the husband's private domain; but if they are (and they almost always are) then it is wholly impermissible for the wife to access and copy them.??
ii) If a wife does access such private documents she is not only in jeopardy of criminal penalties but also risks being civilly sued by the husband for breach of confidence and misuse of his private material.??
iii) If a wife supplies such documents to her solicitor then the solicitor must not read them but must immediately seek to obtain all of them from the wife and must return them, and all copies (both hard and soft), to the husband's solicitor (if he has one). The husband's solicitor, who owes a high duty to the court, will read them and disclose those of them that are both admissible and relevant to the wife's claim, pursuant to the husband's duty of full and frank disclosure11. If before that exercise has taken place the husband's solicitor is dis-instructed the solicitor must retain those documents pending a further order of the court. ??
iv) If the husband does not have a solicitor the wife's solicitor must retain the documents, unread, and in sealed files, and must approach the court for directions. Those directions will likely be to the effect that the wife shall pay for an independent lawyer to be instructed to determine which of those documents are admissible and relevant to the wife's claim. Copies can then be provided to the wife's solicitor before the files of documents are returned to the husband.??
v) The wife is permitted to rely on her knowledge of the documents to challenge the veracity of the husband's disclosure in the proceedings. Her knowledge is admissible evidence. For this purpose she can express her recollection to her solicitor, and the solicitor can advise on it. However, if the expression of that recollection involves the revelation of clearly privileged matters then the solicitor must stop the conversation immediately. If things have gone too far the solicitor will have to consider carefully whether (s)he can continue acting for the wife. It is open to the husband to apply to the court, in the interests of justice, for an order barring the wife from relying on her knowledge in this way. ??
vi) By the same token, if the wife's recollection is that the documents clearly show that the husband is unjustifiably dealing with his assets and that there is therefore a clear risk of dissipation to her prejudice then she can inform her solicitor of this. Subject to the point about privilege mentioned above, the solicitor is entitled to give advice on her recollection and can draft an affidavit in support of a freezing application. But if the wife elects to go down this route she is bound in that affidavit candidly to reveal that her knowledge derives from illegitimately obtained documents, and must explain how she got them. She must do this even if this leads to a civil suit or criminal proceedings. That is the price that she will (potentially) have to pay for making an application based on illegitimately obtained knowledge. Of course, there is no question of the wife being forced to incriminate herself as she has a free choice whether to go down this route.<<
You may, of course, want to change your phone ......
